Alkylation of aromatics



Patented Sept- 3 1947- I UNITED STATES- PATE'NT' "or-ma ALKYLATION AROMATICS Vladimir N. Ipatieif, Chicago, a Carl B. Linn,

Riverside, Ill., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application December 1, 1944, I I Serial No. 566,236

10 Claims. (01. 260-4371) 2 The present invention relates to the interacoils. Benzene may also be produced by the cattion of alkylatable aromatic hydrocarbons with alytic dehydrocyclization of normal hexane or olefinic hydrocarbons in the presence of a novel the catalytic dehydrogenation of cyclohexane.

alkylation catalyst. It is more particularly con- 'Although the boron trifluoride-fluorosulionic cerned with the production of alkylated aromatic 5 acid catalyst is particularly applicable when ethhydrocarbons which can be used in various orylene is employed as the alkylating agent, our

ganic syntheses as starting materials for the invention is broader in scope and the catalyst production of highly desirable resins and similar may be used generally for reacting aromatic hycompounds. a drocarbons with either normally gaseous ornor- The alkylation of aromatics, particularly benmally liquid hydrocarbons, particularly monozene with ethylene, has become very important olefins containing from 2 to about carbon atat the present time. The primary product of the oms per molecule. In some instances diolefinic reaction, ethyl benzene, upon dehydrogenation hydrocarbons can be used. Furthenpolymers of yields substantial quantities of styrene which is lower boiling olefins may also be employed as the now extensively employed in the manufacture oif l5 alkylating agent although not necessarily under synthetic rubber. Ethyl benzene, isopropyl benthe same operating conditions used when emzene and similar compounds have been found to ploying the original mono-olefins.

have excellent antiknock properties and are val- The alkylation of the aromatic hydrocarbons uable as addition. agents to gasolines to produce with olefinic hydrocarbons in the presence of premium motor fuels. 20 boron trifluoride-fiuorosulfonlc acid catayst may Sulfuric acid is well known in the prior art as be carried out at a temperature between 0 a satisfactory catalyst for the interaction of ben- C. to about 100 C., althougha more preferzene with olefins, such as propylene, butylene, able operating range is from about 10 C. to about amylene and higher boiling material. However, 50 C. In any event, the temperature of the this catalyst has been found ineflective for the reaction should be higher than the freezing point ylation of benzene with ethylene since most of the catalyst. It is highly desirable that the of the ethylene reacts with the sulfuric acid to reaction be carried out under sufiicient pressure f m yl sulfuric acid or diethyl sulfate. to maintain a substantial portion of the reactants Ordinarily, when effecting the latter reaction, in liquid phase, for example, from ab t .10 t that is the interaction of benzene and ethylene, about 100 atmospheres,- depending upon the solid catalysts such as aluminum chloride actiamount of boron trifiuoride present. the temvated with hyd n 0h10ride,si1ica-a1umina. t perature of the reaction and upon other factors. have be n empl y d. sts p ess d As is well known in the art of alkylating aroadva es which are inherent in their physical matics with olefins, the hydrocarbon feed to the s ct e- It s Preferable, f possible to malkylation reaction zone should preferably conl y a liquid cataly s at i t e mixing of tain a substantial excess of the aromatic hydrot e a y t a reactants may be obtained. carbons over the olefinic hydrocarbons, for ex- We have dis overed t y use Of a combinaample, a molal ratio of aromatics to olefins of tion of two compounds which individually will from b t 2:1 t b t 20 1 or higher, If denot catalyze the interaction of benzene and eth- 40 sired, the olefinic reactants may be introduced yl a y ctory catalystfor th s r at spaced points throughout the alkylation zone tion is formed. Further, the cat yst is in in order to maintain the de ired hi h aromatic stantially l q P se and possesses the to olefin ratio. It is also preferable that the wavantages inherent in a. liquid catalyst. This new ter content of the catalyst b kept t a minicatalyst comprises a mixture of boron trlfiuoride usually below 5% by we1qht Th in and fiuorosulfonic acid. some instances it may be desirable to snblect the In one embodiment the present invention hydrocarbon ghargingv stock to a drying step comprises a process for the alkylation of aroprior to the introduction. into the alkyation zone. matics with olefins, particularlyethylene in the In the foregoingit has been stated that the presence of boron trifiuoride and fiuorosulionic reaction concerned is that of the interaction of acid. an aromatic with an olefin. However. the general Benzene may be readily obtained from distilbroad scope of this invention includes theme; of

lation of coal tar products or maybe found in compounds which form olefinic hydrocarbons unlarge quantities in straight-run gasolines from der the reaction conditions and do not have-any various crude oils, particularlythe coastal crude 5 deleterious effect on the catalyst activity. In this 3 class may be included such compounds as alkyl fluorides. The termalkylating agent" as used hereinafter in this specification and appended claims is intended to include oleflns and other compounds which react similarly to the olefins under conditions of operation without seriously damaging the activity of the catalyst.

Fluorosulfonic acid is a liquid at ordinary atmospherlc temperatures and pressure. It has a faint pungent odor, it feels greasy to the touch and in contrast to the intense blistering action of hydrogen fluoride it has but little action on the dry skin. The acid boils at 163 C. with slight decomposition. It may be prepared readily by reacting fuming sulfuric acid with fluorspar or by interacting fuming sulfuric acid with anhydrous hydrogen fluoride. Boron trifiuoride has a boiling point of 101 C. and at ordinary temperatures is a colorless gas.

The composite alkylation catalyst of this invention may be utilized in a variety of ways although the most convenient method is to dissolve substantial amounts of the boron trifiuoride in fiuorosulfonic acid. The alkylation process may be conducted in batch or continuous operation but from a commercial point ofview the latter is preferable. The hydrocarbon reactants and catalyst are subjected to intimate contact preferably by meansof a mechanically agitated alkylation zone which is maintained under sufiicient pressure to keep a substantial portion of the reactants and catalyst in the liquid phase. Other types of contacting equipment may also be employed, for example, a so-called time tank wherein intimate contact is obtained by means of a, system of bafiles or orifices. Cooling means such as internal heat exchange zones must also be incorporated in the reaction zone in order to control the temperature of the exothermic alkylation reaction.

The hydrocarbon-catalyst mixture is withdrawn from the reaction zone and introduced into a gravity settling zone or other suitable separation zone. An upper hydrocarbon reaction products layer is withdrawn to a fractionation system while the lower used catalystlayer is preferably recycled to the alkylation zone although a portion thereof may be withdrawn and replaced with fresh catalyst. In certain cases, the withdrawn, used, catalyst may be regenerated and returned to the system. The hydrocarbon. reaction products are fractionated to separate desired alkylation products from unconverted isoparafl'lns. The latter are recycled to the alkylation zone in order to maintain the desired high aromatic to olefin ratio in the hydrocarbon feed stock. Light hy-" drocarbon contaminants in the charging stock to the process may also be removed in the fractionation step in order to prevent their accumulation in the alkylation system. For example, if appreciable amounts of ethane, propane or butanes are introduced by employing a gaseous hydrocarbon fraction as a source of the olefin, it will be desirable to remove these constituents during the fractionation operation.

It may be desirable to agitate the aromatics with fiuorosulfonic acid in the liquid phase and then introduce boron trifiuoride and olefin reactants at spaced points throughout the reaction zone. Other modifications and methods of offecting contact between the aromatic and olefin reactant and the two components of the catalyst will be readily apparent to those skilled in the hydrocarbon conversion art. It is not intended to limit the general broad scope of the present invention to any particular method of contacting the catalyst and the reactants.

The following experimental data are introduced to illustrate the nature of the present invention as it is applied to the alkylation of henzene with ethylene. I

About 240"grams of benzene and 93 grams of fiuorosulfonic acid are present in a nickel-lined stirring autoclave and the autoclave is then sealed. About grams of boron trifiuoride is added under pressure and the stirring begun. Throughout the course of the reaction ethylene is added to the bomb under a pressure of 800 pounds per square inch until the quantity added is about 30 grams. During the addition the bomb is maintained at room temperature and at the end of the test the pressure, if any, on the autoclave is .released through a train containing an alkali scrubber, a calcium chloride drying tower and a condensible gas receiver cooled to 80 C. The

7 reaction product in the autoclave is separated corresponding to ethylbenzene.

We claim as our invention:

1. A process for the synthesis of hydrocarbons which comprises reacting an aromatic hydrocarbon with an alkylating agent under alkylating conditions in the presence of boron trifiuoride and fluorosulfonic acid.

2. A process for the synthesis of hydrocarbons which comprises reacting an aromatic hydrocarbon with an olefinic hydrocarbon under alkylating conditions in the presence of boron trifiuoride I and fluorosulfonic acid.

3. A process for the alkylation of aromatic hydrocarbons with olefinic hydrocarbons which comprises'contacting aromatics and olefins at a temperature from about 0 C. to about C. in the presence of boron trifiuoride and fiuorosulfonic acid.

4. A process for the synthesis of hydrocarbons which comprises alkylating an aromatic hydrocarbon with an Elefin in the presence of boron trifiuoride and fluorosulfonic acid at a temperature of from about 10 C. to about 50 C. under suflicient pressure to maintain the reactants in substantially liquid phase. a

5. A process for the synthesis of hydrocarbons which comprises alkylating benzene with ethylene in the presence of boron trifiuoride and fluorosulfonic acid.

6. A process for the synthesis of hydrocarbons which comprises alkylating benzene with propylene in the presence of boron trifiuoride and fiuorosulfonic acid.

7. A process for the synthesis of hydrocarbons which comprises alkylating benzene with butylene in the presence of boron trifiuoride and fluorosuifonic acid.

8. A process for the synthesis of hydrocarbons which comprises reacting an aromatic hydrocarhon with an alkylating agent in a reaction zone maintained under alkylating conditions and in the presence of boron trifiuoride and fiuorosulionic acid, separating hydrocarbon reaction products from the used alkylating catalyst and recycling at least a portion of said used catalyst to the reaction zone. I

9. An alkylation process which comprises agitating an aromatic hydrocarbon with fluorosulionic acid in the liquid phase in a reaction zone,

introducingboron trifluoride and an alkylating agent at a plurality of spaced points in said reaction zone, and therein reacting said aromatic hydrocarbon with said aikyiating agent under alkylating conditions.

10. The process of claim 9 wherein said aikylating agent comprises ethylene. I

' VLADIMIR N. IPA'ITEEFF.

- CARL B. LINN.

REFERENCES CITED The following references are of record in. the filed this patent:

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